Memory-conjunction errors: Miscombination of stored stimulus features can produce illusions of memory

We demonstrate that subjects will often claim to have previously seen a new stimulus if they have previously seen stimuli containing its component features. Memory for studied stimuli was measured using a "yes"/"no" recognition test. There were three types of test stimuli: target stimuli, which had been presented during study, conjunction stimuli, constructed by combining the features of separate study stimuli, and feature stimuli, in which studied stimulus features were combined with new, unstudied, features. For both nonsense words and faces, the subjects made many more false alarms for conjunction than for feature stimuli. Additional experiments demonstrated that the results were not due to physical similarity between study and test stimuli and that conjunction errors were much more common than feature errors in recall. The results demonstrate that features of stored stimuli maintain some independence in memory and can be incorrectly combined to produce recognition errors.     

Effects of conceptually based familiarity in memory conjunction errors

The authors examined whether the frequency of conjunction errors varied in a recognition test according to the semantic relation between 2 words. Participants studied a series of natural (meaningful) or bizarre Japanese noun phrase patterns and later completed a recognition test that contained old, conjunction, feature, and new stimuli. Participants who studied a list of natural noun phrases did not make any false old responses to unmatched (bizarre) conjunction stimuli. However, participants who studied bizarre noun phrases made as many false old responses to matched (bizarre) conjunction stimuli as to unmatched (natural) conjunction stimuli. The results of the bizarre study stimuli group indicated that bizarre noun phrases may be translated into meaningful stimuli because of mnemonic instruction. Together, the results support the hypothesis that conceptually based familiarity, not pure perceptually based familiarity, influences false old responses to conjunction stimuli.     

Electrophysiological correlates of exemplar-specific processes in implicit and explicit memory

The present ERP study investigated the retrieval of task-irrelevant exemplar-specific information under implicit and explicit memory conditions. Subjects completed either an indirect memory test (a natural/artificial judgment) or a direct recognition memory test. Both test groups were presented with new items, identical repetitions, and perceptually different but conceptually similar exemplars of previously seen study objects. Implicit and explicit memory retrieval elicited clearly dissociable ERP components that were differentially affected by exemplar changes from study to test. In the indirect test, identical repetitions, but not different exemplars, elicited a significant ERP repetition priming effect. In contrast, both types of repeated objects gave rise to a reliable old/new effect in the direct test. The results corroborate that implicit and explicit memory fall back on distinct cognitive representation and, more importantly, indicate that these representations differ in the type of stimulus information stored. Implicit retrieval entailed obligatory access to exemplar-specific perceptual information, despite its being task irrelevant. In contrast, explicit retrieval proved to be more flexible with conceptual and perceptual information accessed according to task demands.     

任务类型对面孔联合效应和特征效应的调节

采用特征-联合范式的研究发现, 面孔再认阶段可记录到明显的联合效应和特征效应; 然而, 与再认同属情景记忆的另一任务(来源提取)条件的相应效应尚未报道, 背景信息一致性对联合面孔和特征面孔提取的调节作用以及面孔不同特征对特征效应的影响也未考察。为澄清上述问题, 本文采用特征-联合范式, 并以位置为背景展开研究。实验含一个学习任务和两个测验任务(再认和来源提取)。结果显示, 再认和来源提取阶段均记录到显著的联合效应和特征效应, 且两类效应均在来源提取阶段更强; 任务类型与位置背景一致性交互影响提取绩效; 面孔外部特征和内部特征对特征效应的影响相似。表明联合效应和特征效应具有显著的任务类型敏感性, 这些效应是联合面孔和特征面孔的熟悉性较强且对源面孔的回忆加工相对较弱的结果, 且这两类面孔的提取为背景一致性所调节; 任务类型对两类效应的调节与双重加工理论模型相吻合。     

Effects of level of processing on emotional memory: gist and details

The object of this study was to investigate whether level of processing (LOP) modulates enhanced memory performance for emotional stimuli, and, if so, whether the LOP effects relate to their gist and details. During the study phase, participants were presented with colourful pictures with negative, neutral and positive valences and encoded the emotional pictures under either a semantic (living/non-living judgement) or a perceptual (left/right position judgement) condition. During the test phase, they judged whether the presented picture was old or new in Experiments 1 and 2, and also judged whether a specific concept, labelled using words, had been studied in Experiment 2. The results showed that under both encoding conditions, the details of both negative and positive pictures were recognised better than those of neutral pictures. Also, the gist of negative pictures was recognised better than that of neutral pictures but only under the semantic condition. These data provide evidence that the LOP differentially modulates enhanced emotional memory for gist and details of pictures.     

语义联系对关联再认神经机制的调节

已有研究显示,关联再认可记录到分别反映双重加工模型的两阶段（即熟悉和回忆）的ERP成分（即FN400和LPC成分）,且具有高语义联系配对的关联再认可通过整合在基于熟悉加工的基础上完成。然而,不同语义联系对关联再认神经机制的影响及单个项目的熟悉和回忆加工的调节作用尚未揭示。为此,本研究比较了主题相关和类别相关图形关联再认的波形波幅异同,并分析了单个项目的熟悉和回忆加工对配对识别的影响。结果显示,主题相关和类别相关条件的旧配对、重组配对和“旧+新”配对均记录到反映熟悉加工的FN400成分,主题相关条件的旧配对、重组配对和“旧+新”配对均记录到反映回忆加工的LPC成分,类别相关条件的旧配对记录到LPC成分。表明关联再认的神经机制受语义联系所调节,单个项目的熟悉程度可影响配对识别时的神经机制,上述结论支持双重加工模型。     

Unitization of Sublexical Components in Implicit Memory for Novel Words

This study examines the role of componential knowledge and unitization processes in implicit memory. In two experiments, subjects studied novel words formed out of morphemes, syllables, or pseudosyllables. They then completed an implicit task requiring a judgment as to which of two items (one old, one new) was a better English word. Experiment 1 replicated previous results showing priming for nonwords formed out of morphemes and syllables but not seudosyllables. This effect was present when orthographic factors were controlled and, unlike explicit (recognition) memory, was equally strong following visual and semantic processing. Experiment 2 showed that little priming was present across a variety of conditions in which the connections between components were altered across study and test. Results are interpreted as evidence for the role of perceptually based activation and integration processes in implicit memory for novel stimuli.     

Disjunction and conjunction fallacies in episodic memory

It has recently been found that episodic memory displays analogues of the well-known disjunction and conjunction fallacies of probability judgement. The aim of the present research was, for the first time, to study these memory fallacies together under the same conditions, and test theoretical predictions about the reasons for each. The focus was on predictions about the influence of semantic gist, target versus context recollection, and proactive versus retroactive interference. Disjunction and conjunction fallacies increased in conditions in which subjects were able to form semantic connections among list words. In addition, disjunction fallacies were increased by manipulations that minimised proactive interference, whereas conjunction fallacies were increased by manipulations that minimised retroactive interference. That pattern suggests that disjunction fallacies are more dependent on target recollection, whereas conjunction fallacies are more dependent on context recollection.     

Trait anxiety and impaired control of reflective attention in working memory

The present study investigated whether the control of reflective attention in working memory (WM) is impaired in high trait anxiety individuals. We focused on the consequences of refreshing—a simple reflective process of thinking briefly about a just-activated representation in mind—on the subsequent processing of verbal stimuli. Participants performed a selective refreshing task, in which they initially refreshed or read one word from a three-word set, and then refreshed a non-selected item from the initial phrase or read aloud a new word. High trait anxiety individuals exhibited greater latencies when refreshing a word after experiencing the refreshing of a word from the same list of semantic associates. The same pattern was observed for reading a new word after prior refreshing. These findings suggest that high trait anxiety individuals have difficulty resolving interference from active distractors when directing reflective attention towards contents in WM or processing a visually presented word.     

The effects of total sleep deprivation on recognition memory processes: A study of event-related potential

This study examined the memorization of information after a night of normal sleep and total sleep deprivation (TSD) by means of event-related potentials (ERPs). We expected a disfacilitatory effect of TSD on memory processing. Eighteen subjects were tested twice in a counterbalanced fashion. During the study session, subjects were presented with unfamiliar face stimuli and asked to memorize them for a subsequent memory test. At the test session, the subjects were presented with the studied faces intermixed with “new” faces and asked to indicate the previously presented stimuli. The N100 was used as a covariate to control for the differences in level of vigilance between the two sessions. Sleep deprivation decreased subjects’ ability to discriminate new from previously studied stimuli and decreased the peak amplitude of the early component (N200) to the decrement of performance. In addition, following TSD the amplitude of the late frontal component (LFC), which is thought to reflect contextual processing, was decreased in covariance with the N100 vigilance component. The amplitude of the late posterior component (LPC/P600) was also reduced but was unrelated to the vigilance component of the ERP. Based on prior studies, this LPC reduction can be interpreted to indicate a decrease in information retrieved after TSD. In summary, a night of TSD decreased the amplitude of the ERPs associated with complex episodic memory task stimuli, affected the frontal cortex during episodic retrieval, and prevented the elaboration process. Furthermore, there was an inability to discriminate what is and what is not in memory, possibly due to less local processing of details.     

IMPLICIT MEMORY IN AMNESIC PATIENTS:

Abstract— Previous observations of spared priming in amnesic patients have been based almost entirely on data from visual implicit memory tests Our research examined perceptual priming.in amnesic patients and control subjects on an auditory identification task in which previously spoken words and new words were presented in white noise We manipulated type of encoding task (semantic vs nonsemantic) and speaker's voice at study and test (same vs different) Priming was little affected.by either manipulation, and amnesic patients exhibited normal priming in all experimental conditions On an explicit test of recognition memory, by contrast, amnesic patients exhibited.severely impaired performance following the semantic study task, all subjects showed poor explicit memory following the nonsemantic study task Results are consistent with the idea that auditory priming depends largely on a presemantic auditory perceptual representation system     

负性情绪对不同语义、空间关系联结记忆的影响

以负性项目-中性场景以及中性项目-中性场景组成的图片对为材料,通过操控项目-场景之间的语义联系和空间距离,考察了负性情绪对不同语义、空间关系联结记忆的影响。结果显示,当项目-场景空间距离较近时,无论项目-场景之间的语义是否相关,负性情绪始终不会影响项目-场景联结记忆;当项目-场景空间距离较远且语义不相关时,负性情绪会削弱项目-场景联结记忆;而当项目-场景空间距离较远且语义相关时,负性情绪会促进项目-场景联结记忆。结果表明,负性情绪对项目-场景联结记忆的影响会受到项目与场景之间语义关系和空间关系的调节,且语义关系在项目-场景空间距离较远时的作用更为突出。     

Recognition memory for related pictures

This study presents a test of the notion of semantic integration of information m pictures. In Experiment 1. subjects were presented pictures which comprised various subsets of the elements in one of four standard pictures. In the test phase. recognition confidence tor old and new items was a direct function of the number of figures in the test picture. However. recognition confidence was significantly higher for old than for new pictures, contrary to predictions of the integration model of Bransford and Franks (1971). In Experiment 2, the differential predictions of the integration model and the tally model (Reitman & Bower, 19731 were tested. The information for a key standard picture was presented solely as ONEs during acquisition. For the other three standard pictures. information was presented as ONEs, TWOs, and THREEs. The results were that recognition confidence increased with complexity at the test item with regular items but decreased with increasing complexity with key items. Together. these experiments support the tally model and demonstrate the generalizabilitv of this model to handle pictorial materials. Implications regarding the nature of picture memory are also discussed.     

The role of sparsely distributed representations in familiarity recognition of verbal and olfactory materials

We present the generalized signal detection theory (GSDT), where familiarity is described by a sparse binomial distribution of binary node activity rather than by normal distribution of familiarity. Items are presented in a distributed representation, where each node receives either noise only, or signal and noise. An old response (i.e., a “yes” response) is made if at least one node receives signal plus noise that is larger than the activation threshold, and item variability is determined by the distribution of activated nodes as the threshold is varied. A distinct representation leads to better performance and a lower ratio of new to old item variability, than a more distributed and less distinct representations. Here we apply the GSDT to empirical data on verbal and olfactory memory and suggest that verbal memory relies on a distinct neural item representation, whereas olfactory memory has a fuzzy neural representation leading to poorer memory and inducing a larger ratio of new to old item variability.     

Phonological Short-term Memory and the Learning of Novel Words: The Effect of Phonological Similarity and Item Length

The investigation of a patient with a selective impairment of phonological short-term memory has recently provided evidence that this system may be involved in long-term learning of novel words, for which a pre-existing semantic representation is not available (Baddeley, Papagno, & Vallar, 1988). The present series of experiments in normal subjects explored this hypothesis. We assessed the effects of phonological similarity and item length, which reflect the operation of the phonological short-term store and the rehearsal component of verbal memory, upon paired associate long-term learning of auditorily presented words and non-words. Phonological similarity affected the learning of novel words more than known words (Experiment 1); when a delay was interposed between presentation and recall, the disruptive effect was confined to novel words (Experiment 2). Also word length disrupted the learning of novel words, but not of known words (Experiment 3). These results tie in with neuropsychological evidence to suggest a role for phonological short-term memory in the learning of new words, and they have developmental implications for the study of language acquisition.     

Remembering words not presented in sentences: How study context changes patterns of false memories

People falsely endorse semantic associates and morpheme rearrangements of studied words at high rates in recognition testing. The coexistence of these results is paradoxical: Models of reading that presume automatic extraction of meaning cannot account for elevated false memory for foils that are related to studied stimuli only by their visual form; models without such a process cannot account for false memory for semantic foils. Here we show how sentence and list study contexts encourage different encoding modes and consequently lead to different patterns of memory errors. Participants studied compound words, such as tailspin and floodgate, as single words or embedded in sentences. We show that sentence contexts led subjects to be better able to discriminate conjunction lures (e.g., tailgate) from old words than did list contexts. Conversely, list contexts led to superior discrimination of semantic lures (e.g., nosedive) from old words than did sentence contexts.     

字频和预存表征对相继记忆效应的影响

采用学习-再认研究范式和事件相关电位方法,研究高频字、低频字、假字和非字的相继记忆效应(Dm效应)。18名大学生为被试,根据其测验结果将刺激分成记住和未记住两类,对相应编码过程的ERPs进行分析。结果表明：（1）真字中发现了相继记忆效应,低频字比高频字的相继记忆效应更大,随后正确再认的ERPs 比不能正确再认的ERPs有更大的晚正成份;（2）非字中的相继记忆效应比真字中的效应更大,出现的时间也较早(140ms~200ms),而假字中没有发现显著的相继记忆效应。这些结果表明,字频是影响相继记忆效应的重要因素,高、低频字的相继记忆效应可能存在不同的神经机制,而预存表征不是相继记忆效应出现与否的前提条件     

New methods,measures, and models for analyzing memory impairment using triadic comparisons

We study the effect of memory impairment on triadic comparisons of animal names in a large clinical data set. We define eight groups of subjects in terms of their delayed free recall performance, and present standard analyses of the triadic comparison and free recall data that provide little insight into the effect of memory impairment on semantic structure. We then develop and apply two new methods for analyzing the data, based on cognitive models and using Bayesian statistical inference. The first new method focuses on modeling changes in semantic representation, by inferring multidimensional scaling (MDS) representations for each group based on their triadic comparisons. These representations reveal a successive decrease in semantic cluster structure and increase in uncertainty with increasing impairment. We propose a measure of spatial organization as a means of quantifying the visually evident changes in semantic organization, and demonstrate its usefulness. The second new method focuses on modeling changes in memory access with impairment, inferring the extent to which each individual makes triadic comparisons consistent with a common semantic representation. Although these inferences are based on just 12 comparisons per subject, we show that they vary systematically with memory impairment group. We conclude by discussing the potential for clinical application of our new models, measures, and methods.